Automatic gas-feed for vacuum-tube lamps.



, I mlm flirzm 777cm r BY No. 856,483. PATENTED JUNE 11, 1907.

D. MOP. MOORE.

AUTOMATIC GAS FEED FOR VACUUM TUBE LAMPS. APPLIOATION FILED MAY a. 1906.

' wmv Esses; INVENTOR ATTORNEYS UNITED STATES PATENT OFFICE.

DANIEL McFARLAN MOORE, OF NEWARK, NEW JERSEY, ASSIGN OR TO MOOREELECTRICAL 00., OF NEW YORK, N. Y, A CORPORATION OF NEW YORK.

AUTOMATIC GAS-FEED FOR VAClJUNl-TUBE LAMPS.

Specification of Letters Patent.

Patented June 11, 1907.

Application filed May 8,1906. Serial No. 315,729.

To (LN/111770727, it may concern:

Be it known that I, DANIEL MCFARLAN Moons, a citizen of the UnitedStates, and a resident of Newark, in the county of Essex and State ofNew Jersey, with post-office address 52 Laurence street, have inventedcertain new and useful Improvements in Automatic Gas-Feeds forVacuum-TubeLamps, of which the following is a specification.

My invention relates to that class of electric lamps known as vacuumtube lamps wherein the source of light is a gas or vapor excited toluminosity by electric energy of any proper form or kind.

The object of my invention is to maintain a constant tension or densityof the gas or vapor within said lamp so as to maintain a constantluminosity.

Briefly stated, my invention consists essentially in supplying gas tothe tube by devices automatically responsive to changes or variations inthe intensity of the light so as to maintain a practically constanttension or density of the gas or vapor.

For simplicity, I show my invention as ap-' plied to a vacuum tube lamphaving, internal electrodes, although, as will be obvious, the nature ofthe electrodes and the manner of furnishing the electric-energy to thegaseous contents may be varied indefinitely without departing from myinvention.

My invention consists also in the specific combinations of devicescomprising amongothers the combination of a vacuum tube, a seleniumcell, means for feeding gas to the tube from a body of gas'of greatertension than t t within the same and an actuating or con rolling magnetconnected to ,a circuit of the selenium cell.

' Referring to the accompanying drawings, Figure 1 is a general sideelevation and partia-l section of an apparatus embodying my inventlon.Flg. 2 shows a modification 1n the manner of making the changes ofresistance of a selenium cell effective to operate a valve. Fig. 3 showsa further modification.

1 is a vacuum tube lamp having the usual or any proper terminal orelectrodes 2 by which electric energy is caused to circulate through thegaseous contents of said tube.

3 is a selenium cell of any desired character exposed to the light ofthe tube and pref- -sources of light. .as a variable resistance in theelectric circult erably inclosed in a box or casing 4 to protect itagainst the influenceof outside Sald selemum cell operates containing orhaving connected to it an electromagnet or other means responsive tovariations of electric current, said magnet being in turn used tocont-rel the operation of the devices which supply the proper gas orvapor to the vacuum tube'l. The gas supplied may be obtained from anysource.

I prefer to feed gas into the tube from a body of gas of greater tensionthan that within the tube, the feed being regulated or controlledthrough the action of a suitable valve. The body of gas-in said tube maybe derived from the atmosphere, a gas generator as described and claimedin my application for patent filed April 16th, 1906,

S. N. 311,815 or a gas converter through When a valve is employed, thesame may be of the kind described in my prior application for patentfiled Aug. 21st, 1905 and in a division of said application filed April16th, 1906, or may be any other construction of valve.

4 is a valve chamber of glass to which gas is supplied through a pipe 5and in which is located the tip of a plug 6 of some porous material likeelectric light carbon, which plug.

fits in the end of a tube 7 through which the gas is fed to the tube.Surrounding the plug 6 is a body of mercury 8, which surrounds thetapered plug. By changing the level of the mercury to expose or concealthe pointed tip of the plug or more or less of said tip, the flow of gasfrom said chamber 4 through the porous material of the plug to thefeedpipe 7 may be varied. Normally the tipis more or less concealedbeneath the level of the liquid and little or no gas can flow, but whenthe level falls, the tip is exposed or is more exposed and gas may fiowin minute amount. The changes of level in the liquid by which the valveaction is produced may be brought IuO about by any means responsive tochanges in the resistance of the selenium cell. As a type of suchdevices, I show an electromagnet 9 included in the circuit of any sourceof electric energy 10' and selenium cell 3., The movable core of saidmagnet is properly attached to a plunger or displacer 1 1 which 7 worksin the body of mercury surrounding plug 8. Other means might be employedfor bringing about the change in the level of the liquid when theresistance in the selenium cell 3 changes.

In the operation of this apparatus, the valve may be so adjusted byadjusting the position of the magnet coils that no portion of the tipwill be exposed above the mercury, and hence no gas will flow, so longas the density or tension of the gas in tube 1 is at the normal so as togive a light of the normal intensity The adjustment-might, however, besuch that under the conditions supposed, a very little of the tip wouldbe exposed. The

density or tension of gas in the tubebeing of such a degree that adecrease of tension will have the eflect of lowering the resistance ofthe gas to the passage of the current, any decrease of such densitybelow normal will permit more current to flow andhence increase theintensity of the light. This variation in the intensity of the lightwill, by acting directly upon the selenium cell, produce a change ofelectric resistance therein, lowering such resistance and therebyincreasing the power of the electromagnet 9 which latter causes thevalve to open and feed gas or more gas to'the tube 1. As soon as the gastension or density has thus been brought back to normal, the light willfall in intensity to normal and the resistance of the selenium cell willincrease owing to the less action of. the light thereof so that themagnet 9 will decrease in power and the plunger will be permitted todrop back in order to close or partially close the valve. This act1on isrepeated upon any increase of gas tension or density in the tube 1requiring an additional supply of gas to bring the tension back tonormal. q The changes of resistance due to the changes in the intensityof the light may be made effective, obviously, through other devicesresponsive to change in current flow, thus for instance, the circuit ofthe selenium cell may, as shown inFig. 2, be provided with an electricheater typified as a coil 12 which is in shunt to the selenium cell sothat a decrease of resistance itself will bring, about a decrease ofcurrent flow in the heater. The heater typified as a mere resistancecoil may be applied to a chamber 13 containing a body of mercuryconnecting through a pipe 14 with the chamber containing the mercuryseal for the valve. Obviously, the expansion of the mercury, due to theaction of the holder, will maintain the mercury at such height as ftothe level of the mercury around the tip of the 4 plug to drop slightlyand 'feed gas to the tube 1,

Preferably, the relative bulk of the mercury in the valve chamber tothat in the chamber 13 is small in order to secure a delicate action ofthe device when the tension of the gas in the tube 1 has been restoredto normal and the intensity of the light brought back to normal theselenium cell will, through increase of its resistance, force morecurrent into theheater and cause an expansion of the mercury, so as toclose or more completely close the valve and cut off the supply of gas.

Many other variations in the apparatus will suggest themselves toelectricians as suitable for causing gas to be supplied to the tube whenthe current in a circuit is modified or changed through changes ofaction of a selenium cell exposed to the light of the tube.

A selenium cell is shown as typical of all devices adapted to respond tovariations in the intensity of light in a manner to bring about thephysical action that may be utilized electrically or mechanically tovary the supply of gas to the tube.

The selenium cell may be used as a generator of energy when exposed tothe light of the tube and the source 10 be removed from the circuitthereof. This modification is shown in Fig. 3. In this form the cellfurnishes current influctuating amount to an electromagnet 20, and theelectromagnet 9 is in a circuit connected to the armature and contactpoint of electromagnet 20 as shown. Normally, the circuit of the magnet9 is opened but when, through increase of light in the tube, the cellgenerates more energy, magnet 20 closes the circuit of the coils forelectromagnet 9 and the latter acts to open the valve. Suitableadjustment of the valve in all cases may be secured by adjusting theposition of the coils of the electromagnet 9 1n Figs. 1 and 2 or byadjusting the number of turns in the heater coil or by any othersuitable means.

What I claim as my iiivention is:

1. The method of maintaining a gas tension or density of a vacuum tubelamp at normal by supplying gas thereto in accordance with variations inthe intensity of the light of said tube. v

2. The method of maintaining the luminous condition of a vacuum tubelamp at its normal by regulating the admission of gas to said lampthrough variations in the intensity of the light of said lamp.

3. The combination of a vacuum tube lamp, a selenium cell exposed to thelight ot said lamp and means responsive to variations in the resistanceof said cell for supplying gas to the lamp.

4. The combination of a vacuum tube lamp, a selenium cell exposed to thelight of said lam and means responsive to variations in t e resistanceof saidcell for feeding gas to the lam from a body of gas of greaterdensitv than t at in the lamp:

5. The combination of a vacuum tube -lam a selenium cell exposed to theaction of t 10 light of said la1n a valve through which gas may be fedto t e lamp, and means responsive to variations in the resistance of'responsive to variations in the intensity of the light. Signed atNeWYork in the county of New York and State of New York this 5th day of MayA. D. 1906. l

DANIEL MCFARLAN MOORE.

Witnesses:

C. F. TISCHNER, Jr., LILLIAN BLQND.

